A conventional variable capacity type vane pump is known which varies the eccentricity of a cam ring with respect to a rotor to vary a discharge capacity by pivoting the cam ring about a pin.
In the variable capacity type vane pump of this type, since an inner pressure (pressure in a pump chamber) produced inside the cam ring acts on the inner peripheral surface of the cam ring, the cam ring is biased in a direction to pivot toward one side about a pivot point by the inner pressure of the cam ring.
JP2003-74479A discloses a vane pump in which a pivot point of a cam ring is so arranged that an inner pressure of the cam ring acts in a return direction to return the cam ring in a direction to increase a discharge capacity and a spring is provided to bias the cam ring in the return direction.